In recent years, there is a trend for increasing the hardness of steel plates that are used in the field of industrial machinery in abrasive environments such as mines, civil engineering, agricultural machines and construction in order to, for example, extend the life of grinding ability to grind ores into powders.
However, increasing the hardness of steel is generally accompanied by a decrease in low-temperature toughness and consequently causes a risk that the steel may be cracked during use. Thus, there has been a strong demand for the enhancement in the low-temperature toughness of high-hardness abrasion resistant steel plates, in particular, abrasion resistant steel plates having a Brinell hardness of 361 or more.
Approaches to realizing abrasion resistant steel plates with excellent low-temperature toughness and methods for manufacturing such steel plates have been proposed in the art such as in Patent Literatures 1, 2 and 3 in which low-temperature toughness is improved by optimizing the carbon equivalent and the hardenability index.